This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This project involves the structure determination of an octameric peptide that forms amyloid fibrils. Crystals with a long needle habit formed spontaneously from a D2O solution. We will determine the structure of the crystalline peptide using X-ray crystallography, utilizing a microfocus beamline in order to accommodate the extremely small size of the crystals (cross section approximately 3 x 3 micron). Because this peptide has a sequence that is significantly different from those of amyloid peptides of known structure, we anticipate that this structure will provide new information about the possible packing modes available to peptides and proteins in the fibrillar state.